mirror of
https://github.com/prometheus/prometheus.git
synced 2026-02-10 10:21:19 +01:00
55193c3058
Fix incorrect interpolation when counter resets occur in smoothed range selector evaluation. Previously, the asymmetric handling of counter resets (y1=0 on left edge, y2+=y1 on right edge) produced wrong values. Now uniformly set y1=0 when a counter reset is detected, correctly modeling the counter as starting from 0 post-reset. This fixes rate calculations across counter resets. For example, rate(metric[10s] smoothed) where metric goes from 100 to 10 (a reset) now correctly computes 0.666... by treating the counter as resetting to 0 rather than producing inflated values from the old behavior. Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
121 lines
3.6 KiB
Go
121 lines
3.6 KiB
Go
// Copyright The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package promql
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import (
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"fmt"
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"math"
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"testing"
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"github.com/prometheus/common/model"
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"github.com/stretchr/testify/require"
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"github.com/prometheus/prometheus/model/histogram"
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"github.com/prometheus/prometheus/model/labels"
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"github.com/prometheus/prometheus/promql/parser/posrange"
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)
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func TestHistogramRateCounterResetHint(t *testing.T) {
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points := []HPoint{
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{T: 0, H: &histogram.FloatHistogram{CounterResetHint: histogram.CounterReset, Count: 5, Sum: 5}},
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{T: 1, H: &histogram.FloatHistogram{CounterResetHint: histogram.UnknownCounterReset, Count: 10, Sum: 10}},
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}
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labels := labels.FromMap(map[string]string{model.MetricNameLabel: "foo"})
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fh, _ := histogramRate(points, false, labels, posrange.PositionRange{})
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require.Equal(t, histogram.GaugeType, fh.CounterResetHint)
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fh, _ = histogramRate(points, true, labels, posrange.PositionRange{})
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require.Equal(t, histogram.GaugeType, fh.CounterResetHint)
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}
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func TestKahanSumInc(t *testing.T) {
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testCases := map[string]struct {
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first float64
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second float64
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expected float64
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}{
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"+Inf + anything = +Inf": {
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first: math.Inf(1),
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second: 2.0,
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expected: math.Inf(1),
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},
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"-Inf + anything = -Inf": {
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first: math.Inf(-1),
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second: 2.0,
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expected: math.Inf(-1),
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},
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"+Inf + -Inf = NaN": {
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first: math.Inf(1),
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second: math.Inf(-1),
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expected: math.NaN(),
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},
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"NaN + anything = NaN": {
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first: math.NaN(),
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second: 2,
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expected: math.NaN(),
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},
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"NaN + Inf = NaN": {
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first: math.NaN(),
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second: math.Inf(1),
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expected: math.NaN(),
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},
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"NaN + -Inf = NaN": {
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first: math.NaN(),
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second: math.Inf(-1),
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expected: math.NaN(),
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},
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}
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runTest := func(t *testing.T, a, b, expected float64) {
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t.Run(fmt.Sprintf("%v + %v = %v", a, b, expected), func(t *testing.T) {
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sum, c := kahanSumInc(b, a, 0)
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result := sum + c
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if math.IsNaN(expected) {
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require.Truef(t, math.IsNaN(result), "expected result to be NaN, but got %v (from %v + %v)", result, sum, c)
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} else {
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require.Equalf(t, expected, result, "expected result to be %v, but got %v (from %v + %v)", expected, result, sum, c)
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}
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})
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}
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for name, testCase := range testCases {
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t.Run(name, func(t *testing.T) {
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runTest(t, testCase.first, testCase.second, testCase.expected)
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runTest(t, testCase.second, testCase.first, testCase.expected)
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})
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}
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}
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func TestInterpolate(t *testing.T) {
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tests := []struct {
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p1, p2 FPoint
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t int64
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isCounter bool
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expected float64
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}{
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{FPoint{T: 1, F: 100}, FPoint{T: 2, F: 200}, 1, false, 100},
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{FPoint{T: 0, F: 100}, FPoint{T: 2, F: 200}, 1, false, 150},
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{FPoint{T: 0, F: 200}, FPoint{T: 2, F: 100}, 1, false, 150},
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{FPoint{T: 0, F: 200}, FPoint{T: 2, F: 0}, 1, true, 0},
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{FPoint{T: 0, F: 200}, FPoint{T: 2, F: 100}, 1, true, 50},
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{FPoint{T: 0, F: 500}, FPoint{T: 2, F: 100}, 1, true, 50},
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{FPoint{T: 0, F: 500}, FPoint{T: 10, F: 0}, 1, true, 0},
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}
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for _, test := range tests {
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result := interpolate(test.p1, test.p2, test.t, test.isCounter)
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require.Equal(t, test.expected, result)
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}
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}
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